The purpose of the proposed research is to identify, isolate, and characterize a bacterial binding protein with high specificity for human immunoglobulin M (IgM) constant region determinants. This reagent would have applications for early identification of individuals exposed to pathogens, detection of infections in the newborn, and a variety of immunodiagnostic tests for monitoring disease progression. We propose to apply highly selective assay techniques to screen a large number of isolates from a wide variety of sources. This methodology has been developed by Dr. Michael Boyle, the Principal Investigator, to detect and purify bacterial binding molecules for other human plasma proteins. Once a strain is found that binds human IgM in the appropriate fashion, the protein will be isolated and its binding characteristics studied in detail. Information gained in the Phase I study will provide the foundation for the eventual production of a wide array of derivatives which will be useful to researchers, manufacturers of diagnostic kits, and producers of antibodies. Well established genetic engineering techniques can be used to manipulate the properties of the molecule and to facilitate large scale production of the reagent when the commercialization stage is reached.